refactor: update ParserHelper

- update the implementation of ParserHelper from locale-based std::to_string, std::stod, std::stoull, to locale-independent function std::from_chars and std::to_chars.
- rename TerminalHelper to ConsoleHelper.

src/CMakeLists.txt

@@ -1,13 +1,13 @@
 # Setup file lists up
 set(YYCC_HEADER ${CMAKE_CURRENT_LIST_DIR})
 set(YYCC_SRC
+    ConsoleHelper.cpp
     DialogHelper.cpp
     EncodingHelper.cpp
     ExceptionHelper.cpp
     IOHelper.cpp
     ParserHelper.cpp
     StringHelper.cpp
-    TerminalHelper.cpp
 )
 
 # Create static library

src/ConsoleHelper.cpp

@@ -1,4 +1,4 @@
-#include "TerminalHelper.hpp"
+#include "ConsoleHelper.hpp"
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 #include "EncodingHelper.hpp"
@@ -11,7 +11,7 @@
 #include <fcntl.h>
 #include "WinImportSuffix.hpp"
 
-namespace YYCC::TerminalHelper {
+namespace YYCC::ConsoleHelper {
 
 	bool EnsureTerminalColor(FILE* fs) {
 		if (!_isatty(_fileno(fs))) return false;

src/ConsoleHelper.hpp

@@ -5,7 +5,7 @@
 #include <cstdio>
 #include <string>
 
-namespace YYCC::TerminalHelper {
+namespace YYCC::ConsoleHelper {
 	
 #define YYCC_TERMCOLHDR_BLACK "\033[30m"
 #define YYCC_TERMCOLHDR_RED "\033[31m"

src/ParserHelper.hpp

@@ -6,55 +6,45 @@
 #include <cinttypes>
 #include <type_traits>
 #include <stdexcept>
-#include <limits>
+#include <charconv>
+#include <array>
 
 namespace YYCC::ParserHelper {
 
-	template<class>
-	constexpr bool g_AlwaysFalse = false;
+	// Reference: https://zh.cppreference.com/w/cpp/utility/from_chars
 
 	template<typename _Ty, std::enable_if_t<std::is_floating_point_v<_Ty>, int> = 0>
 	bool TryParse(const std::string& strl, _Ty& num) {
-		try {
-			// float types
-			if constexpr (std::is_same_v<_Ty, float>) {
-				num = std::stof(strl, nullptr);
-			} else if constexpr (std::is_same_v<_Ty, double>) {
-				num = std::stod(strl, nullptr);
-			} else if constexpr (std::is_same_v<_Ty, long double>) {
-				num = std::stold(strl, nullptr);
-			} else {
-				static_assert(g_AlwaysFalse<_Ty>, "Invalid float type.");
-			}
-			return true;
-		} catch (const std::invalid_argument&) {
+		auto [ptr, ec] = std::from_chars(strl.c_str(), strl.c_str() + strl.size(), num, std::chars_format::general);
+		if (ec == std::errc()) {
+			// check whether the full string is matched
+			return ptr == strl.c_str() + strl.size();
+		} else if (ec == std::errc::invalid_argument) {
+			// given string is invalid
 			return false;
-		} catch (const std::out_of_range&) {
+		} else if (ec == std::errc::result_out_of_range) {
+			// given string is out of range
 			return false;
+		} else {
+			// unreachable
+			throw std::runtime_error("unreachable code.");
 		}
 	}
 	template<typename _Ty, std::enable_if_t<std::is_integral_v<_Ty> && !std::is_same_v<_Ty, bool>, int> = 0>
 	bool TryParse(const std::string& strl, _Ty& num, int base = 10) {
-		try {
-			// integer type
-			// decide integer type
-			using container_t = std::conditional_t<std::is_unsigned_v<_Ty>, unsigned long long, long long>;
-			// parse it from string according to whether integer type is signed.
-			container_t cache;
-			if constexpr (std::is_unsigned_v<_Ty>) {
-				cache = std::stoull(strl, nullptr, base);
-			} else {
-				cache = std::stoll(strl, nullptr, base);
-			}
-			// check its range
-			if (cache < std::numeric_limits<_Ty>::min() || cache > std::numeric_limits<_Ty>::max())
-				return false;
-			num = static_cast<_Ty>(cache);
-			return true;
-		} catch (const std::invalid_argument&) {
+		auto [ptr, ec] = std::from_chars(strl.c_str(), strl.c_str() + strl.size(), num, base);
+		if (ec == std::errc()) {
+			// check whether the full string is matched
+			return ptr == strl.c_str() + strl.size();
+		} else if (ec == std::errc::invalid_argument) {
+			// given string is invalid
 			return false;
-		} catch (const std::out_of_range&) {
+		} else if (ec == std::errc::result_out_of_range) {
+			// given string is out of range
 			return false;
+		} else {
+			// unreachable
+			throw std::runtime_error("unreachable code.");
 		}
 	}
 	template<typename _Ty, std::enable_if_t<std::is_same_v<_Ty, bool>, int> = 0>
@@ -72,12 +62,25 @@ namespace YYCC::ParserHelper {
 		return ret;
 	}
 
-	template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty>, int> = 0>
+	// Reference: https://en.cppreference.com/w/cpp/utility/to_chars
+
+	template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty> && !std::is_same_v<_Ty, bool>, int> = 0>
 	std::string ToString(_Ty num) {
-		return std::to_string(num);
+		std::array<char, 64> buffer;
+		auto [ptr, ec] = std::to_chars(buffer.data(), buffer.data() + buffer.size(), num);
+		if (ec == std::errc()) {
+			return std::string(buffer.data(), ptr - buffer.data());
+		} else if (ec == std::errc::value_too_large) {
+			// too short buffer
+			// this should not happend
+			throw std::out_of_range("ToString() buffer is not sufficient.");
+		} else {
+			// unreachable
+			throw std::runtime_error("unreachable code.");
+		}
 	}
-	template<>
-	std::string ToString<bool>(bool num) {
+	template<typename _Ty, std::enable_if_t<std::is_same_v<_Ty, bool>, int> = 0>
+	std::string ToString(_Ty num) {
 		if (num) return std::string("true");
 		else return std::string("false");
 	}

src/YYCCommonplace.hpp

@@ -4,6 +4,6 @@
 
 #include "StringHelper.hpp"
 #include "EncodingHelper.hpp"
-#include "TerminalHelper.hpp"
+#include "ConsoleHelper.hpp"
 #include "DialogHelper.hpp"
 #include "ParserHelper.hpp"